Patent EP-4164090-A1 (EP)
Inventor: BLASZCZYK PAWEL
IPC: H02J50/60
Filed: 2021-10-06
Abstract: A contactless power supply device (10) for a contactless charging system comprising a high frequency generator (11) for generating a high frequency waveform, an oscillation unit (12) with a primary coil (13) for generating an alternating flux and a control unit (14) for controlling operation of the high frequency generator (11). The output of the high frequency generator (11) is connected to the primary coil (13) of the oscillation unit (12) and the output of the control unit (14) is connected to the input of the high frequency generator (11). Furthermore, the contactless power supply device (10) comprises a measuring unit (15) configured to measure instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system, or to measure the RMS values I<sub>RMS</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system, or the contactless power supply device (10) comprises a measuring unit (15) configured to measure instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system and the control unit (14) is configured to calculate the RMS values I<sub>RMS</sub> of the measured instantaneous values I<sub>meas</sub> of alternating current, or to calculate the change rate didt of the measured instantaneous values I<sub>meas</sub> of alternating current, wherein di - a first degree differential of the measured instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), dt - a first degree differential of measurement time of the instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), or to calculate a second derivative d2idt2 of the measured instantaneous values I<sub>meas</sub> of alternating current, wherein d<sup>2</sup>i - a second degree differential of the measured instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), dt<sup>2</sup> - a second degree differential of measurement time of the instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), or the control unit (14) is configured to measure instantaneous values I<sub>meas</sub>of alternating current of the primary coil (13) during a charging state of a contactless charging system, or to measure the RMS values I<sub>RMS</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system, or to measure instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system and calculate the RMS values I<sub>RMS</sub> of the measured instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system, or to measure instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system and calculate the change rate didt of the measured instantaneous values I<sub>meas</sub> of alternating current, wherein di - a first degree differential of the measured instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), dt - a first degree differential of measurement time of the instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), or to measure instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13) during a charging state of a contactless charging system and calculate the second derivative d2idt2 of the measured instantaneous values I<sub>meas</sub> of alternating current, wherein d<sup>2</sup>i - a second degree differential of the measured instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), dt<sup>2</sup> - a second degree differential of measurement time of the instantaneous values I<sub>meas</sub> of alternating current of the primary coil (13), and said contactless power supply device (10) is configured to detect a foreign object between the power supply device (10) and a power receiver device of a contactless charging system such that instantaneous values I<sub>meas</sub> of alternating current are measured, or the RMS values I<sub>RMS</sub> of alternating current are measured and/or calculated, or the change rate didt of the measured instantaneous values I<sub>meas</sub> of alternating current is calculated, the second derivative d2idt2 of the measured instantaneous values I<sub>meas</sub> of alternating current is calculated, and the foreign object is detected when the measured instantaneous value I<sub>meas</sub> of alternating current is equal or greater than a set threshold value I<sub>limit</sub> of alternating current, or the measured and/or calculated RMS value I<sub>RMS</sub> of the measured instantaneous value I<sub>meas</sub> of alternating current is equal or greater than a set threshold value of the RMS value I<sub>RMS limit</sub>, or the calculated change rate didt of the measured instantaneous value I<sub>meas</sub> of alternating current is equal or greater than a set threshold value of the change rate didtlimit, or the calculated second derivative d2idt2 of the measured instantaneous value I<sub>meas</sub> of alternating current is equal or greater than a set threshold value of the second derivative d2idt2limit